We present a novel variational framework for performing inference in (neural) stochastic differential equations (SDEs) driven by Markov-approximate fractional Brownian motion (fBM). SDEs offer a versatile tool for modeling real-world continuous-time dynamic systems with inherent noise and randomness. Combining SDEs with the powerful inference capabilities of variational methods, enables the learning of representative function distributions through stochastic gradient descent. However, conventional SDEs typically assume the underlying noise to follow a Brownian motion (BM), which hinders their ability to capture long-term dependencies. In contrast, fractional Brownian motion (fBM) extends BM to encompass non-Markovian dynamics, but existing methods for inferring fBM parameters are either computationally demanding or statistically inefficient. In this paper, building upon the Markov approximation of fBM, we derive the evidence lower bound essential for efficient variational inference of posterior path measures, drawing from the well-established field of stochastic analysis. Additionally, we provide a closed-form expression to determine optimal approximation coefficients. Furthermore, we propose the use of neural networks to learn the drift, diffusion and control terms within our variational posterior, leading to the variational training of neural-SDEs. In this framework, we also optimize the Hurst index, governing the nature of our fractional noise. Beyond validation on synthetic data, we contribute a novel architecture for variational latent video prediction,-an approach that, to the best of our knowledge, enables the first variational neural-SDE application to video perception.

在这篇论文中，我们提出了一种用于推断由Markov-近似分数布朗运动（fBM）驱动的（神经）随机微分方程（SDEs）的新颖变分框架。我们结合了SDEs和变分方法的强大推断能力，通过随机梯度下降学习代表性函数分布。此外，我们还提出了一种使用神经网络学习变分后验中的漂移、扩散和控制项的方法，从而实现了神经-SDEs的变分训练。我们还优化了Hurst指数，控制分数噪声的性质。最后，我们提出了一种用于变分潜在视频预测的新型架构。

分数噪声驱动的随机微分方程的变分推断